Embodiments of the invention relate generally to synthetic jet actuators and, more particularly, to the packaging of synthetic jet actuators.
Synthetic jet actuators are a widely-used technology that generates a synthetic jet of fluid to influence the flow of that fluid over a surface. A typical synthetic jet actuator comprises a housing defining an internal chamber. An orifice is present in a wall of the housing. The actuator further includes a mechanism in or about the housing for periodically changing the volume within the internal chamber so that a series of fluid vortices are generated and projected in an external environment out from the orifice of the housing. Examples of volume changing mechanisms may include, for example, a piston positioned in the jet housing to move fluid in and out of the orifice during reciprocation of the piston or a flexible diaphragm as a wall of the housing. The flexible diaphragm is typically actuated by a piezoelectric actuator or other appropriate means.
Typically, a control system is used to create time-harmonic motion of the volume changing mechanism. As the mechanism decreases the chamber volume, fluid is ejected from the chamber through the orifice. As the fluid passes through the orifice, sharp edges of the orifice separate the flow to create vortex sheets that roll up into vortices. These vortices move away from the edges of the orifice under their own self-induced velocity. As the mechanism increases the chamber volume, ambient fluid is drawn into the chamber from large distances from the orifice. Since the vortices have already moved away from the edges of the orifice, they are not affected by the ambient fluid entering into the chamber. As the vortices travel away from the orifice, they synthesize a jet of fluid, i.e., a “synthetic jet.”
Due to their inclusion of flexible diaphragms piezoelectric actuator elements, it is recognized that synthetic jet actuators are fragile mechanisms. As synthetic jet actuators can be subjected to a range of environment conditions during use, this can lead to occurrences of pre-mature failure and to the need for replacement of the synthetic jet actuators. Such replacement of the synthetic jet actuators can be time consuming and, in some cases, can also necessitate shutdown of the system or components to which the synthetic jet actuators are designed to provide cooling to. It would thus be beneficial for the synthetic jet actuator be protected from the surrounding environment such that the synthetic jet actuator may be protected from temperature extremes, moisture, and physical impact from surrounding components.
Accordingly, there is a need for a system and method for packaging synthetic jet actuators so as to provide protection from environmental conditions. There is a further need for such a system to have minimal impact on the operation and performance of the synthetic jet actuators.